Technical-Economical Study on the Optimization of FDM Parameters for the Manufacture of PETG and ASA Parts

The article presents the results of the technical–economical study regarding the optimization of fused deposition modeling (FDM) parameters (the height of the layer deposited in one pass—Lh and the filling percentage—Id) for the manufacture of Polyethylene Terephthalate Glycol (PETG) and Acrylonitrile Styrene Acrylate (ASA) parts. To carry out this technical–economical study, was used the fundamental principle of value analysis, which consists of maximizing the ratio between Vi and Cp, where Vi represents the mechanical characteristic, and Cp represents the production cost. The results of the study show that for tensile specimens made of PETG, the parameter that significantly influences the results of the Vi/Cp ratios is the height of the layer deposited in one pass, (Lh), and in the case of the compression specimens made of PETG, the parameter that significantly influences the results of the Vi/Cp ratios is filling percentage (Id). In the case of specimens manufactured via FDM from ASA, the parameter that decisively influences the results of the Vi/Cp ratios of the tensile and compression specimens is the filling percentage (Id). By performing optimization of the process parameters with multiple responses, we identified the optimal parameters for FDM manufacturing of parts from PETG and ASA: the height of the layer deposited in one pass, Lh = 0.20 mm, and the filling percentage, Id = 100%.

The additive manufacturing process represents a major innovation in the field of manufacturing, enabling the transformation of digital concepts into physical objects [29][30][31][32][33][34].This process encompasses several essential steps to ensure the transition from digital design to the final physical product:  In [4], innovative strategies are presented for the technical-economical optimization of the parameters of 3D printing via FDM (L h -the height of the deposited layer in one pass; I d -the filling percentage).To optimize the parameters, the value analysis method was used, which consists of maximizing the ratio between the use value (V i ) and the production cost (C p ).The use value is represented by the mechanical characteristics.The results of the study show that of the two parameters considered (L h and I d ), the height of the layer deposited at one pass decisively influences the bending resistance, and I d categorically influences the resistance to breaking and compression, but also the hardness.The optimal parameters for printing PLA via FDM are L h 0.15 mm and I d 100%, those for heat-treated PLA are 0.20 mm and I d 100%, and those for ABS are L h 0.15 mm and I d 100%.
In [35], the authors present a study on the optimization of FDM parameters (I d -filling percentage; L h -height of the deposited layer in one pass; W n -number of walls; E t -extruder temperature; P s -printing speed; B t -platform temperature; N l -the number of lower and upper layers; I p -the filling pattern) to minimize energy consumption, but without affecting the traction characteristics.The conclusions show that the parameters that categorically influence the energy consumption, but also the traction characteristics, are I d , L h , W n , and B t , and their optimal values are as follows: I d -90%; L h -0.30 mm; W n -4; B t -60 • C.
In [36], a study is presented on the optimization of FDM parameters (N d -extrusion nozzle diameter; W n -number of walls; E t -extruder temperature; I d -filling percentage; I p -filling pattern) to reduce the printing time, but without affecting the mechanical properties of the parts.The results of the study show that the parameters that decisively influence the printing time are as follows: N d , I d , and W n .Research suggests that a larger nozzle diameter (N d = 0.60 mm), four outer shells (W n = 4), and a 10% infill (I d = 10%) can reduce print time without compromising mechanical characteristics.
In [37], the authors presents a study regarding the impact of FDM parameters (L h -height of the deposited layer in one pass; E t -extruder temperature; P s -printing speed; B t -platform temperature) on the compression behavior of samples made of PLA filament, and its use in biomedical and clinical applications is investigated.The considered FDM parameters significantly influenced the mechanical properties, and statistical simulations and SEM (scanning electron microscopy) analyses showed the ability to improve the mechanical properties.The conclusions of the study show that the highest value of the compressive strength (C s ) was obtained for the samples made with the following parameters: L h = 0.10 mm; T e = 205 • C, B t = 60 and P s = 50 mm/min.ANOVA certified that the parameter that decisively influences the compressive strength (C s ) is the height of the layer deposited at one pass (L h ).
In [9], a study is presented on the influence of the filling pattern (I p ) on the compressive strength of parts manufactured via FDM from PLA.In this context, 28 samples were manufactured on the Anycubic 4 Max Pro 2.0 3D printer using seven filling patterns (Grid, Tri-Hexagon, Octet, Triangles, Cubic subdivision, Gyroid, Cross-3D).The dimensions of the specimens were measured before and after the compression test using a DeMeet 3D coordinate measuring machine.The results show a minimum printing accuracy of 98.98% and a maximum deformation value of 57.70% for the specimens with the Triangles fill pattern.The highest values of compressive strengths were obtained for the specimens with the Triangles filling pattern.To establish the optimal option from a technical-economical point of view, a maximization of the ratio between the use value (V i ) and the production cost (C p ) was carried out, this ratio being one of the fundamental technical-economical principles of the value analysis.The Cubic subdivision fill pattern is the most efficient method for the FDM fabrication of PLA compression specimens using lattice structures.

Advantages: + high quality of surfaces;
+ high print speed.

Disadvantages:
-significant loss of material.-laborious post-processing of printed objects.

Disadvantages:
-significant loss of material.
-laborious post-processing of printed objects.

Advantages:
+ simple technology; + low-cost materials and equipment.

Disadvantages:
-poor-quality surfaces of parts; -low printing speed.Advantages: + high-resistance parts; + good precision of parts.

Disadvantages:
-poor quality of surfaces poor; -high-cost equipment and materials.

Disadvantages:
-fragile parts; -poor quality of surfaces poor.
Advantages: + use of high-performance materials; + high resistance of parts.

Disadvantages:
-high-cost equipment and materials; -long duration required for cooling parts.Advantages: + high-resistance parts; + good precision of parts.

Disadvantages:
-poor quality of surfaces poor; -high-cost equipment and materials.

Advantages:
+ simple technology; + low-cost materials and equipment.
Disadvantages: -poor-quality surfaces of parts; -low printing speed .
Advantages: + high-resistance parts; + good precision of parts.

Disadvantages:
-poor quality of surfaces poor; -high-cost equipment and materials.

Disadvantages:
-fragile parts; -poor quality of surfaces poor.
Advantages: + use of high-performance materials; + high resistance of parts.

Disadvantages:
-high-cost equipment and materials; -long duration required for cooling parts.Advantages: + high printing speed; + reduced costs for materials and equipment.

Disadvantages:
-fragile parts; -poor quality of surfaces poor.

Advantages:
+ simple technology; + low-cost materials and equipment.

Disadvantages:
-poor-quality surfaces of parts; -low printing speed .
Advantages: + high-resistance parts; + good precision of parts.

Disadvantages:
-poor quality of surfaces poor; -high-cost equipment and materials.

Disadvantages:
-fragile parts; -poor quality of surfaces poor.
Advantages: + use of high-performance materials; + high resistance of parts.

Disadvantages:
-high-cost equipment and materials; -long duration required for cooling parts.Advantages: + use of high-performance materials; + high resistance of parts.

Disadvantages:
-high-cost equipment and materials; -long duration required for cooling parts.
In the following, attention will be paid to the use of additive manufacturing technology through thermoplastic extrusion, this being one of the most widespread additive manufacturing technologies due to its ease of use, but also because of its low costs of equipment and materials (see Table 1).
This paper presents a technical-economical study regarding the optimization of the FDM parameters (Lh-the height of the layer deposited in one pass and Id-the filling percentage) for the manufacture of tensile and compression specimens from PETG and ASA.The novelty of this study consists in the application of the fundamental principle of value analysis (AV), which aims to maximize the ratio between the use value (Vi) and the production cost (Cp).Thus, we will establish the optimal FDM parameters for the manufacture of tensile and compression specimens from PETG and ASA.

Materials and Methods
The variable parameters of FDM used in the manufacture of tensile and compression specimens from PETG and ASA are the height of the deposited layer in one pass, Lh = (0.10/0.15/0.20)mm and the filling percentage Id = (50/75/100)%.The mechanical properties 1-liquid polymer tanks; 2-print head; 3-construction platform; 4-piece; 5-piece support.
In the following, attention will be paid to the use of additive manufacturing technology through thermoplastic extrusion, this being one of the most widespread additive manufacturing technologies due to its ease of use, but also because of its low costs of equipment and materials (see Table 1).
This paper presents a technical-economical study regarding the optimization of the FDM parameters (L h -the height of the layer deposited in one pass and I d -the filling percentage) for the manufacture of tensile and compression specimens from PETG and ASA.The novelty of this study consists in the application of the fundamental principle of value analysis (AV), which aims to maximize the ratio between the use value (V i ) and the production cost (C p ).Thus, we will establish the optimal FDM parameters for the manufacture of tensile and compression specimens from PETG and ASA.

Materials and Methods
The variable parameters of FDM used in the manufacture of tensile and compression specimens from PETG and ASA are the height of the deposited layer in one pass, L h = (0.10/0.15/0.20)mm and the filling percentage I d = (50/75/100)%.The mechanical properties of tensile (tensile strength, percentage elongation at break and elastic modulus) and compressive (compressive stress), were previously determined by the authors in works [48,49], respectively [50,51].
Using the parameters from Table 2, 54 tensile specimens (27 of PETG and 27 of ASA), in accordance with [52], and 90 compression specimens (45 of PETG and 45 of ASA) were manufactured on the Anycubic Pro Max 2.0 3D printer (Shenzhen, China), in accordance with [53].Tensile and compression specimens made from Everfil PETG and ASA filament on the Anycubic Pro Max 2.0 3D printer were tested on the Barrus White 20 kN universal testing machine.Following the realization of the experimental determinations for the two types of mechanical tests (tension and compression), as well as the calculation of the production cost for each set of samples, a technical-economical study on the optimization of the FDM parameters was carried out.To establish the optimal variant, the fundamental principle of value analysis was used, which is presented in relation 1, and which consists of maximizing the ratio between the use value (V i ) and the production cost (C p ) [4,9,[56][57][58][59].This fundamental principle of value analysis is an effective tool for multi-objective optimization processes because it is value-driven and cost-effective, and it simplifies the decision process because it offers clear and easy-to-follow objective functions.
where V i represents the value in use (mechanical characteristic), and C p represents the production cost expressed in monetary units.Minitab 19 software was used to optimize the ratio between V i and C p .To calculate the production cost, the following relationship was used [4,9,[56][57][58][59]: The dimensions and test conditions of the tensile and compression specimens are shown in Table 4.Following the realization of the experimental determinations for the two types of mechanical tests (tension and compression), as well as the calculation of the production cost for each set of samples, a technical-economical study on the optimization of the FDM parameters was carried out.To establish the optimal variant, the fundamental principle of value analysis was used, which is presented in relation 1, and which consists of maximizing the ratio between the use value (Vi) and the production cost (Cp) [4,9,[56][57][58][59].This fundamental principle of value analysis is an effective tool for multi-objective optimization processes because it is value-driven and cost-effective, and it simplifies the decision process because it offers clear and easy-to-follow objective functions.
where Vi represents the value in use (mechanical characteristic), and Cp represents the production cost expressed in monetary units.Minitab 19 software was used to optimize the ratio between Vi and Cp.To calculate the production cost, the following relationship was used [4,9,[56][57][58][59]: where The dimensions and test conditions of the tensile and compression specimens are shown in Table 4.

Tensile Testing
Tables 5 and 6 show the results obtained from the application of relation 2 and the determination of the production cost for the tensile specimens manufactured via FDM from PETG and ASA.FDM parameters impact the mechanical behavior of parts made of PETG and ASA, but also the consumption of electricity [35].The results of the V i /C p ratio are shown in Tables 7 and 8.   Analyzing Figure 1, we notice that the highest value of the ratio between Vi (ultimate tensile strength) and Cp (production cost) was obtained for the set of specimens made of ASA with the layer height deposited at a pass of Lh = 0.20 mm and with a percentage of filling of Id = 100%.In the case of specimens made of PETG, the highest value of the ratio between Vi and Cp was obtained for the set of specimens with the layer height deposited at a pass of Lh = 0.20 mm and with a filling percentage of Id = 100%.Comparing the minimum and maximum results of the Vi/Cp ratios of the ASA samples with those obtained for the PETG samples, it was found that for the ASA samples, the results are 13.94-37.23% higher compared to the results of the Vi/Cp ratios of the samples made from PETG.
Using the Minitab 19 software, we performed ANOVA (analysis of variances), which includes sets of statistical methods and procedures used to analyze differences between means, [62].In our study, we used ANOVA to evaluate the relationship between the FDM Analyzing Figure 1, we notice that the highest value of the ratio between V i (ultimate tensile strength) and C p (production cost) was obtained for the set of specimens made of ASA with the layer height deposited at a pass of L h = 0.20 mm and with a percentage of filling of I d = 100%.In the case of specimens made of PETG, the highest value of the ratio between V i and C p was obtained for the set of specimens with the layer height deposited at a pass of L h = 0.20 mm and with a filling percentage of I d = 100%.Comparing the minimum and maximum results of the V i /C p ratios of the ASA samples with those obtained for the PETG samples, it was found that for the ASA samples, the results are 13.94-37.23% higher compared to the results of the V i /C p ratios of the samples made from PETG.
Using the Minitab 19 software, we performed ANOVA (analysis of variances), which includes sets of statistical methods and procedures used to analyze differences between means, [62].In our study, we used ANOVA to evaluate the relationship between the FDM parameters (L h and I d ) and the result of the ratio between V i (ultimate tensile strength) and C p (production cost) [42].Figure 2 shows the result of the ANOVA.Analyzing Figure 2, we observe how the two considered parameters (Lh and Id) affect the result of the Vi/Cp ratio of the tensile specimens made of PETG (Figure 2a) and ASA (Figure 2b).According to Figure 2a, the layer height deposited in one pass (Lh) was the parameter that significantly influenced the result of the Vi/Cp ratio of the tensile specimens made of PETG.Analyzing Figure 2b, we notice that the filling percentage (Id) was the parameter that decisively influenced the result of the Vi/Cp ratio of the tensile specimens made of ASA.The same conclusions are suggested by the Pareto charts shown in Figure 3.

Compressive Testing
Tables 9 and 10 present the results obtained following the application of relation 2 and the determination of the production cost for the compression specimens manufactured via FDM from PETG and ASA.
Tables 11 and 12 show the Vi/Cp results for the compression specimens manufactured via FDM from PETG and ASA.Analyzing Figure 2, we observe how the two considered parameters (L h and I d ) affect the result of the V i /C p ratio of the tensile specimens made of PETG (Figure 2a) and ASA (Figure 2b).According to Figure 2a, the layer height deposited in one pass (L h ) was the parameter that significantly influenced the result of the V i /C p ratio of the tensile specimens made of PETG.Analyzing Figure 2b, we notice that the filling percentage (I d ) was the parameter that decisively influenced the result of the V i /C p ratio of the tensile specimens made of ASA.The same conclusions are suggested by the Pareto charts shown in Figure 3.  Analyzing Figure 2, we observe how the two considered parameters (Lh and Id) affect the result of the Vi/Cp ratio of the tensile specimens made of PETG (Figure 2a) and ASA (Figure 2b).According to Figure 2a, the layer height deposited in one pass (Lh) was the parameter that significantly influenced the result of the Vi/Cp ratio of the tensile specimens made of PETG.Analyzing Figure 2b, we notice that the filling percentage (Id) was the parameter that decisively influenced the result of the Vi/Cp ratio of the tensile specimens made of ASA.The same conclusions are suggested by the Pareto charts shown in Figure 3.

Compressive Testing
Tables 9 and 10 present the results obtained following the application of relation 2 and the determination of the production cost for the compression specimens manufactured via FDM from PETG and ASA.
Tables 11 and 12 show the Vi/Cp results for the compression specimens manufactured via FDM from PETG and ASA.

Compressive Testing
Tables 9 and 10 present the results obtained following the application of relation 2 and the determination of the production cost for the compression specimens manufactured via FDM from PETG and ASA.Tables 11 and 12 show the V i /C p results for the compression specimens manufactured via FDM from PETG and ASA.Analyzing Figure 4, we notice that the highest value of the ratio between Vi (compressive strength) and Cp (cost of production) was obtained for the set of samples made of ASA with the height of the layer deposited at a pass of Lh = 0.20 mm and with a filling percentage of Id = 100%.In the case of specimens made of PETG, the highest value of the ratio between Vi and Cp was obtained for the set of specimens with the layer height deposited at a pass of Lh = 0.20 mm and with a filling percentage of Id = 100%.Comparing the minimum and maximum results of the Vi/Cp ratios of the ASA samples with those obtained for the PETG samples, it is found that for the ASA samples the results are 12.47-20.42%higher compared to the results of the Vi/Cp ratios of the samples made from PETG.
Figure 5 shows the results of the ANOVA, during which the relationship between the FDM parameters (Lh and Id) and the result of the ratio between Vi (compressive strength) and Cp (production cost) was studied.
Analyzing Figure 6, we observe how the two considered parameters of FDM (Lh and Analyzing Figure 4, we notice that the highest value of the ratio between V i (compressive strength) and C p (cost of production) was obtained for the set of samples made of ASA with the height of the layer deposited at a pass of L h = 0.20 mm and with a filling percentage of I d = 100%.In the case of specimens made of PETG, the highest value of the ratio between V i and C p was obtained for the set of specimens with the layer height deposited at a pass of L h = 0.20 mm and with a filling percentage of I d = 100%.Comparing the minimum and maximum results of the V i /C p ratios of the ASA samples with those obtained for the PETG samples, it is found that for the ASA samples the results are 12.47-20.42%higher compared to the results of the V i /C p ratios of the samples made from PETG.
Figure 5 shows the results of the ANOVA, during which the relationship between the FDM parameters (L h and I d ) and the result of the ratio between V i (compressive strength) and C p (production cost) was studied.

Optimization of FDM Parameters Based on Value Analysis for Improving the 3D Printing Efficiency for Samples Made of PETG and ASA
Using Minitab 19, the FDM parameters presented in Table 2 and the results obtained via applying the fundamental principle of value analysis by maximizing the Vi/Cp ratio, we optimized the FDM parameters with the aim of achieving technical-economical efficiency.
To optimize the FDM parameters, we used the desirability method, where the goal was to maximize the values of the ratios between Vi and Cp for each type of mechanical test (tension and compression) and each type of material (PETG and ASA).Table 13 presents optimization objectives for each studied material.Analyzing Figure 6, we observe how the two considered parameters of FDM (L h and I d ) affect the result of the V i /C p ratio of compression specimens made of PETG (Figure 5a) and ASA (Figure 5b).According to Figure 6a, the filling percentage (I d ) is the parameter that significantly influences the V i /C p ratio result of compression specimens made of PETG.Analyzing Figure 5b, we notice that the filling percentage (I d ) is the parameter that decisively influences the result of the V i /C p ratio of the ASA compression specimens.The same conclusions are suggested by the Pareto charts shown in Figure 6.

Optimization of FDM Parameters Based on Value Analysis for Improving the 3D Printing Efficiency for Samples Made of PETG and ASA
Using Minitab 19, the FDM parameters presented in Table 2 and the results obtained via applying the fundamental principle of value analysis by maximizing the Vi/Cp ratio, we optimized the FDM parameters with the aim of achieving technical-economical efficiency.
To optimize the FDM parameters, we used the desirability method, where the goal was to maximize the values of the ratios between Vi and Cp for each type of mechanical test (tension and compression) and each type of material (PETG and ASA).Table 13 presents optimization objectives for each studied material.2 and the results obtained via applying the fundamental principle of value analysis by maximizing the V i /C p ratio, we optimized the FDM parameters with the aim of achieving technical-economical efficiency.
To optimize the FDM parameters, we used the desirability method, where the goal was to maximize the values of the ratios between V i and C p for each type of mechanical test (tension and compression) and each type of material (PETG and ASA).Table 13 presents optimization objectives for each studied material.For the desirability study, we used the following relationships [3]: where D-composite desirability; n-number of responses; d i ¯the desirability for each individual response, y i , L i , T i -the predicted value, target value, and lowest value, respectively, of the analyzed response of response.Table 14 shows the composite desirability for each printing parameter and each type of material.

Conclusions
This paper presents the results of a technical-economical study regarding the optimization of FDM parameters for the manufacture of PETG and ASA parts.In this context, we carried out multi-objective optimization with the aim of finding the optimal FDM parameters (Lh-the height of the deposited layer in one pass; Id-the filling percentage) for the manufacture of PETG and ASA parts.Following the determination of the mechanical characteristics (tensile and compression) of the specimens manufactured via FDM from PETG and ASA, but also the determination of the production cost for each set of specimens, using the fundamental principle of value analysis by maximizing the Vi/Cp ratio, we achieved the technical-economical optimization of the FDM parameters.
Layer height at one pass (Lh) and infill density (Id) are crucial parameters for 3D printing via FDM.This conclusion is highlighted in many studies, such as [4,[33][34][35][36][37][48][49][50][51].Lh has an impact on layer adhesion, surface finish, and defects, and a smaller layer height generates higher tensile strength and compressive strength.Id has an impact on the internal structure; a higher infill density generates higher tensile and compressive strength.
The results of the ANOVA show that the two FDM parameters considered (Lh-the height of the layer deposited in one pass; Id-the filling percentage) influence the results of the Vi/Cp ratios.For tensile specimens made of PETG, the parameter that significantly influences the results of the Vi/Cp ratios is Lh, the height of the layer deposited in one pass, and in the case of compression specimens made of PETG, the parameter that significantly influences the results of the Vi/Cp ratios is Id-the filling percentage.
In the case of specimens manufactured via FDM from ASA, the parameter that decisively influences the results of the Vi/Cp ratios of the tensile and compression specimens is Id-the filling percentage.
Using the results of the Vi/Cp ratios for the tensile and compression specimens made of PETG and ASA, we found the optimal FDM parameters: Lh = 0.20 mm and Id = 100%.According to Figure 7a, following the optimization process of the FDM parameters for PETG, the results of the optimal settings were as follows: layer height (L h ) = 0.20 mm and infill density (I d ) = 100%.Analyzing Figure 7b, we notice that following the optimization process of the FDM parameters for ASA, the results of the optimal settings were as follows: layer height (L h ) = 0.20 mm and infill density (I d ) = 100%.Increasing the layer height per pass (L h ) has a significant impact on print time; this leads to lower power consumption, and thus lower production costs.The decrease in the height of the layer deposited at a pass (L h ) has a direct impact on production costs, but also on maintenance costs, which increase considerably.

Conclusions
This paper presents the results of a technical-economical study regarding the optimization of FDM parameters for the manufacture of PETG and ASA parts.In this context, we carried out multi-objective optimization with the aim of finding the optimal FDM parameters (L h -the height of the deposited layer in one pass; I d -the filling percentage) for the manufacture of PETG and ASA parts.Following the determination of the mechanical characteristics (tensile and compression) of the specimens manufactured via FDM from PETG and ASA, but also the determination of the production cost for each set of specimens, using the fundamental principle of value analysis by maximizing the V i /C p ratio, we achieved the technical-economical optimization of the FDM parameters.
Layer height at one pass (L h ) and infill density (I d ) are crucial parameters for 3D printing via FDM.This conclusion is highlighted in many studies, such as [4,[33][34][35][36][37][48][49][50][51].L h has an impact on layer adhesion, surface finish, and defects, and a smaller layer height generates higher tensile strength and compressive strength.I d has an impact on the internal structure; a higher infill density generates higher tensile and compressive strength.
The results of the ANOVA show that the two FDM parameters considered (L h -the height of the layer deposited in one pass; I d -the filling percentage) influence the results of the V i /C p ratios.For tensile specimens made of PETG, the parameter that significantly influences the results of the V i /C p ratios is L h , the height of the layer deposited in one pass, and in the case of compression specimens made of PETG, the parameter that significantly influences the results of the V i /C p ratios is I d -the filling percentage.
In the case of specimens manufactured via FDM from ASA, the parameter that decisively influences the results of the V i /C p ratios of the tensile and compression specimens is I d -the filling percentage.
Using the results of the V i /C p ratios for the tensile and compression specimens made of PETG and ASA, we found the optimal FDM parameters: L h = 0.20 mm and I d = 100%.
The results of the study have applicability for the efficient exploitation of 3D printers for the manufacture of PETG and ASA parts via FDM.
For the next direction of study, our proposition is to extrapolate the study to other types of materials such as recycled PETG and recycled ASA, but also to other types of mechanical tests such as resilience, flexural, and hardness testing.Also, we want to perform microscopic analyses on parts to investigate microstructure and interface adhesion condition.For the ASA and recycled ASA parts, we plan to choose a broader range of infill densities, I d = (25; 50; 75; 100) %, and layer heights, L h = (0.10; 0.15; 0.20; 0.25; 0.30), mm to capture non-linear trends of ASA parts.For the achievement of the desired objectives, a new FDM 3D printer was purchased (Piocreat G5 Pro), and we were able to manufactured samples via FDM from granular material.

-
CAD conceptualization; -Saving the CAD model and converting it into STL format; -Generating the G-Code file; -Equipment preparation, construction, extraction and use of parts.
)where C p represents the production cost (EUR); C mat represents the cost of the material (EUR); C en represents the energy cost (EUR); Q mat represents the quantity of used material (g); P mat represents the material price (EUR/g); P t represents the printing time (h); E c represents the energy consumption (kW); P en represents the price of electrical energy (euro/kWh).The following constant values were used to perform the economical calculations: P m = 0.22 Euro/g (for PETG); P m = 0.23 Euro/g (for ASA); P en = 0.25 kW/h; E c = 0.23 kW/h[60].The material consumption and print time values for each set of samples were generated by Cura Slicer version 5.7.2, [61].
represents the production cost (EUR);   represents the cost of the material (EUR);   represents the energy cost (EUR);   represents the quantity of used material (g);   represents the material price (EUR/g);   represents the printing time (h);   represents the energy consumption (kW);   represents the price of electrical energy (euro/kWh).The following constant values were used to perform the economical calculations:   = 0.22 Euro/g (for PETG);   = 0.23 Euro/g (for ASA);   = 0.25 kW/h;   = 0.23 kW/h [60].The material consumption and print time values for each set of samples were generated by Cura Slicer version 5.7.2, [61].

3. Results and Discussion 3 . 1 .
Applications of Value Analysis for Analyzing the Mechanical Behavior of PETG and ASA 3D-Printed Samples 3.1.1.Tensile Testing Tables 5 and 6 show the results obtained from the application of relation 2 and the determination of the production cost for the tensile specimens manufactured via FDM from PETG and ASA.Polymers 2024, 16, 2260 7 of 17

Figure 1
Figure 1 graphically shows the values of the ratios between Vi (ultimate tensile strength) and Cp (production cost) of the samples manufactured via FDM from PETG and ASA.

Figure 1 .
Figure 1.Determination of Vi/Cp ratio for tensile samples made from PETG and ASA.

Figure 1 .
Figure 1.Determination of V i /C p ratio for tensile samples made from PETG and ASA.

Polymers 2024 ,
16,  x FOR PEER REVIEW 9 of 17 parameters (Lh and Id) and the result of the ratio between Vi (ultimate tensile strength) and Cp (production cost)[42].Figure2shows the result of the ANOVA.(a) (b)

Figure 4
Figure 4 graphically shows the values of the ratios between V i (compressive strength) and C p (cost of production) of the samples manufactured via FDM from PETG and ASA.

Figure 4 .
Figure 4. Determination of Vi/Cp ratio for compressive samples made from PETG and ASA.

Figure 4 .
Figure 4. Determination of V i /C p ratio for compressive samples made from PETG and ASA.

3. 2 .
Optimization of FDM Parameters Based on Value Analysis for Improving the 3D Printing Efficiency for Samples Made of PETG and ASA Using Minitab 19, the FDM parameters presented in Table

Figure 7
Figure 7 shows the plots of FDM parameter optimizations for the manufacture of PETG and ASA samples.Analyzing Figure 7, we observe how each factor (column) influences the composite desirability response (row).The vertical solid red lines indicate the current setting of the factors, and the red numbers on each column indicate the current level of the factors.The blue horizontal dashed lines indicate the responses corresponding to the current factor settings, and the blue numbers indicate the response corresponding to the current factor settings.

Table 1
details the main additive manufacturing technologies, including the components, operating principles, and advantages and disadvantages of each technology.

Table 1
details the main additive manufacturing technologies, including the components, operating principles, and advantages and disadvantages of each technology.

Table 1
details the main additive manufacturing technologies, including the components, operating principles, and advantages and disadvantages of each technology.

Table 1
details the main additive manufacturing technologies, including the components, operating principles, and advantages and disadvantages of each technology.

Table 2 .
FDM printing parameters used to manufacture tensile and compressive samples from PETG and ASA [48-51].

Table 3
shows the technical specifications of the Everfil filament used in the manufacture of tensile and compression specimens from PETG and ASA.Adapted with permission from [54,55], 2024, 3DKORDO.

Table 3 .
Recommended printing parameters and physical properties of Everfil PETG and ASA filament.

Table 4 .
Testing conditions and samples dimensions for experimental investigation.

Table 3 .
Recommended printing parameters and physical properties of Everfil PETG and ASA filament.

Table 4 .
Testing conditions and samples dimensions for experimental investigation.

Table 5 .
Cost calculation for PETG samples used for tensile testing.

Table 5 .
Cost calculation for PETG samples used for tensile testing.

Table 6 .
Cost calculation for ASA samples used for tensile testing.

Table 7 .
Determination of V i /C p ratio for tensile samples made from PETG.

Table 8 .
Determination of V i /C p ratio for tensile samples made from ASA.
Figure 1 graphically shows the values of the ratios between V i (ultimate tensile strength) and C p (production cost) of the samples manufactured via FDM from PETG and ASA.

Table 8 .
Determination of Vi/Cp ratio for tensile samples made from ASA.

Table 9 .
Cost calculation for PETG samples used for compressive testing.

Table 10 .
Cost calculation for ASA samples used for compressive testing.

Table 11 .
Determination of V i /C p ratio for compressive samples made from PETG.

Table 12 .
Determination of V i /C p ratio for compressive samples made from ASA.

Table 13 .
Optimization goals for analyzed materials (PETG and ASA).